Multiaxis optical viewing system of a movable electron beam in a vacuum chamber



412} g m1 2 W Sept. 2, 1969 s. w. LARSON 3,465,119

MULTIAXIS OPTICAL VIEWING SYSTEM OF A MOVABLE ELECTRON BEAM IN A VACUUM CHAMBER. Filed June 21, 1967 FIG.

INVENTOR SWAN W. LARSON BY M K. Q 7

ATT RNE United States Patent us. or. 219-121 3 Claims ABSTRACT OF THE DISCLOSURE An apparatus for coaxial viewing of the area being worked by an electron beam in a vacuum chamber Where the electron beam generator is provided with two dimensional movement. Optical observation means are provided for continuous observation of the workpiece regardless of the location of the electron beam generator relative to the workpiece as the same is moved thereacross.

Background of the invention In the operation of electron beam machines such as described in the patent to Steigerwald, 2,987,610, it is often desirable to be able to observe the workpiece right at the point where the beam is active. In several systems, an electron beam is used which moves about inside the vacuum and is provided with two-dimensional movement to provide optimum work area coverage. When an electron beam generator is provided with such two-dimensional movement, the observation of the area being worked by the beam is made more difficult in that an observer located outside the vacuum chamber may not always be able to observe the area being worked by the beam through the lead glass window.

Summary of the invention It is, therefore, an object of this invention to provide an optical viewing system which allows an observer, from outside a vacuum chamber, to monitor the area being worked by a movable electron beam gun inside the chamher.

It is a further object of this invention to provide an optical viewing system which allows an observer to continually monitor via an axial viewing system the workpiece being worked by a movable gun inside the chamber.

Description of the preferred embodiment These objects are accomplished by an invention shown in the drawings and described hereafter wherein FIG. 1 is a top viewof the electron beam chamber and the apparatus for moving it'as well as the optical viewing system, and FIG. 2 is the side view of the embodiment shown in FIG. 1. I

In FIG. 2 an electron beam device 1 is shown working on a workpiece 2. The electron beam device 1 is mounted within a chamber 3 and has a wire coupling 4 for supplying power and control signals thereto. A hose -5 is also coupled to the electron beam device 1 to provide the high vacuum needed to operate the electron beam. Such hose will not be needed in the event the entire chamber 3 is evacuated to the hard vacuum level necessary for generation of the beam. The electron beam device may be such as described in United States Patent No. 2,987,610. The electron beam device 1 is made movable in a plane approximately parallel to the workpiece 2 so that the hose 5 and the power and control cable cable 4 are provided with sufficient slack. Inside the electron beam device 1 is a column surrounded by a tubular member 6 and around 3,465,119 Patented Sept. 2, 1969 the tubular member 6 is a mirror 7 which may also be a pentaprism such as shown in the patent to Radtke 3,169,183. The main function of the mirror 7 is to allow an observer to view the workpiece and point of application 8 along the same axis that the electron beam travels. The entire column of the electron beam device 1 is shown mounted on a first member 10 which is threaded and rotated by a motor 11 connected to the threaded member via conventional gearing 12. The electron beam device 1 is mounted in threaded relationship with the first member 10 so that as this member 10 is rotated the beam traverses either left or right depending on the direction of rotation. The other side of first member 10 is supported on a transverse mechanism 13. This mechanism is parallel to a similar transverse supporting mechanism 14 shown in FIG. 1. Both traverse supporting mechanisms 13 and 14 are movable along parallel axes transverse to the movement along the axial member 10.

An optical telescope 15, as shown in FIG. 2, includes a first lens 16 and second lens 17 and in between a mirror 18 mounted in such a manner that light from a source 19 and collimated by lens 20 can be directed onto the spot 8 along the electron beam axis. The mirror 18 is provided with an aperture 21 to allow optical observation from outside the vacuum chamber 3.

In FIG. 1 a mirror 22 is shown connected to the transverse mechanism 13 and positioned to reflect the optical axis through the aperture 21 to an eyepiece telescope arrangement 23. The telescope 23 includes a refocusing lens 24, a reticle 25 and an eyepiece 26.

Since the lenses 16 and 17 of telescope 15 are provided with such characteristics necessary to render the light from the spot 8 to become collimated light as it traverses towards the telescope 23, it makes no difference Where the electron beam device 1 may be located along the first member 10 and an observer at eyepiece 26 can view the electron beam work spots. The reflecting mirror 22 may constitute either a 45 mounted mirror or a pentaprism and its movement is slaved to the transfer mechanism 13 and 14. The telescope or collimator 15 is slaved to the electron beam device 1 and has a relative movement possible along two axes relative to the eyepiece 26.

The transverse movement of these supporting mechanisms 13 and 14 is actuated by a motor 27 which rotates a second member 28 which is in threaded relationship with the supporting mechanism 14. The transverse supporting mechanism 13 may be slidably mounted on a member 29 so that transverse motion of the axial member 10 and the electron beam device 1 may be controlled only from the second threaded member 28. -It is possible, however, to interconnect members 28 and 29 so that both rotate at the same speed in which case also the transverse mechanism 13 is in threaded relationship with the member 29. The actuation of the electric motors 27 and 11 is determined by the operator of the machine. In the operation of this invention one can appreciate that no matter where the electron beam device 1 is located in the chamber, the synchronous relationship between the mirror 22, the collimated light piece 15 and the eyepiece telescope 23 allows for continuous observation and improved control of the apparatus.

It is to be understood that the invention is not limited to the specific embodiment herein illustrated and described but may be used in other ways without departure from its spirit as defined by the following claims.

Having thus described my invention, what I claim is:

1. A device for observing the operation of a movable beam generator located in an evacuated work chamber and having an optical beam viewing system for projecting an image of the beam workpoint along a first axis angled with respect to the beam axis comprising:

means for moving the beam generator parallel to the first axis and parallel to a second axis perpendicular to the first axis and the beam axis;

the means including a support member, the sup port member being movable within the chamber parallel to the second axis, the beam generator being supported by the member and movable on the member in a direction parallel to the first axis; optical observation means having an optical axis and fixedly mounted to the chamber to enable observation of the inside of the chamber, said optical axis oriented substantially parallel to the second axis and intersecting the first axis; and a mirror mounted on the support member at the intersection of the optical axis and the first axis and refleeting the projected image of the beam Workpoint from the optical beam viewing system substantially along the second axis to the observation means. 2. A device as recited in claim 1 wherein the first axis and the beam axis are perpendicular.

3'. A device as recited in claim 1 wherein the generator and support member have engaging portions, the portions being threadably engaged and rotatable with respect to one another to provide the movement of the generator with respect to the member.

References Cited UNITED STATES PATENTS 2,987,610 6/1961 Steigerwald 219-121 3,112,391 11/1963 Sciaky 219-121 3,156,810 11/1964 Samuelson 219-121 3,169,183 2/1965 Radtke et a1 219-121 3,283,120 11/1966 Spruck 219-121 3,300,618 1/1967 Sciaky 219-121 3,383,492 5/1968 Solomon 219-121 JOSEPH V. TRUHE, Primary Examiner W. DEXTER BROOKS, Assistant Examiner 

